Circular knitting machine having welt hooks which cooperate only with alternate needles



3,225,569 HIGH V. LUCHI Dec. 28, 1965 CIRCULAR KNITTING MACHINE HAVINGWELT HOOKS W COOPERATE ONLY WITH ALTERNATE NEEDLES Filed April 14, 19642 Sheets-Sheet 1 w 0 WW 5 WM NA .m 0 F a w M F W 7 5 M SW 3,225,569 HIGH2 Sheets-Sheet 2 K Na OOKS W DLES Fig. 6

Fig-9 E 7F 76 7H 71 VH1 {NW V. LUCHI CHINE HAVING WELT H WITH ALTERNATENEE N4 FI JOH COOPERATE ONLY Fig. 8

gn L/3B CIRCULAR KNITTING MA 7cF7D 7e '7 Dec. 28, 1965 Filed April 14,1964 United States Patent 3,225,569 CIRCULAR KNITTING MACIHNE HAVINGWELT HOOKS WHICH COOPERATE ONLY WITH ALTERNATE NEEDLES Vinicio Luchi,Florence, Italy, assignor to Solis Societal a Responsabilita Limitata,Florence, Italy, a corporation of Italy Filed Apr. 14, 1964, Ser. No.359,719 Claims priority, application Italy, Apr. 17, 1963, 7,775/ 63 1Claim. (Cl. 66-95) This invention relates to circular knitting machinesfor hosiery manufacture.

In conventional machines of this type, a welt hook dial is provided,coaxially above the needle cylinder in which radial tricks are cut witha pair of welt hooks in each trick. These welt hooks are relatively thinand so shaped as to allow the insertion of a cylinder needle into thespace between the two hooks housed in the same trick of the dial. Thisarrangement has disadvantages both with regard to the accuracy requiredin the timing between the needle cylinder and the dial, and with regardto the necessary thinness of the welt hooks, because of the limitedspace between the needles of the cylinder.

The present invention provides a circular knitting hosiery machinehaving a welt hook dial formed with continuous radial tricks which areof constant width throughout their lengths, each of the tricks having asingle flat welt hook slidable therein, and wherein the needles are socontrolled that at the start of the welt formation selected needles areraised so that each of the initial stitches of the welt is supported bytwo welt hooks, whilst at the end of the welt formation, the firstselected needles are raised and after the insertion of the welt hookothers of the needles are raised to deliver the stitches supported bythe pairs of spaced welts hooks.

The present invention also provides a circular knitting hosiery machinehaving a welt hook dial in which each welt hook is angularly spaced bytwo needle spaces from the adjacent welt hooks, wherein one-half of thecylinder needles, equal in number to the welt hooks, are kept lowered atthe start and end of the welt formation, and wherein the needles of thecylinder are so selected at the start of the welt formation that oneneedle at the end of each group of four adjacent needles is raised,whereby each of the initial stitches of the welt is supported by twoadjacent but spaced welt hooks and at the end of the welt formation, theneedles of the cylinder are once again so selected that the one needlein each group of four adjacent needles is again raised, the welt hooksare inserted, the middle needle in each group of three lowered needlesis now raised to enter into the stitch supported by the adjacent pair ofwelt hooks, and the initial stitches are knitted into the fabric.

The invention will be better understood from the following descriptionof one embodiment of the invention which is given, by way of example,with reference to the accompanying drawings in which:

FIG. 1 is a partial diametrical section through a needle cylinder andthe mechanism for forming a welt;

FIGS. 2 and 3 are sections on the lines II-II and III-III of FIG. 1;

FIG. 4 is a perspective view of a welt hook;

FIGS. 5, 6, 7, 8, and 9 are diagrammatical developments of part of thecylinder needles and welt hooks, illustrating five stages of operationof the needles and welt hooks, namely the start of the welt formationduring the welt formation and three stages of clearing the welt hooks atthe end of the welt formation;

FIGS. 10 and 11 diagrammatically illustrate the positions of the needlesas they cooperate with the welt hooks; and

"ice

FIGS. 12 and 13 illustrate and compare the conventional arrangement ofwelt hooks with that according to the invention.

As can be seen in the accompanying drawings, in particular withreference to FIGS. 1 to 3, the machine has a stationary dial cap 1provided with an annular rim 2, which is also stationary and forms a camtrack. The profile of this track includes an inwardly inclined portion2a, and a concave portion 2b to act on the butts 3a of welt hooks 3during their re-insertion, the hooks rotating in the direction of thearrow F of FIG. 2. A sleeve 1a surrounds the control shaft 4 of the dial5. This dial 5 is provided with a plurality of radial tricks 6 (see FIG.3) equal in number to half the number of needles in the needle cylinder.A single welt hook 3 is housed in each trick, and the distance betweenadjacent tricks 6 is such that at the needle circumference, the distancebetween adjacent hooks is equal to the distance between alternateneedles 7 of the needle cylinder 8. The longitudinal axes of the tricks6 intersect the longitudinal axes of alternate ones of the needlepositions. Each hook 3 is flat and thick. The dial 5 is coupled to theshaft 4 by a flanged member 9, which carries a bevel gear 10 meshingwith a pinion 11 for driving a yarn-cutting device, of which only adrive shaft is shown.

The control cams for the butts 3a of the welt hooks are also arranged onthe stationary dial cap 1. In particular, a cam 13 is provided to effecta small radial outward movement of the hooks each to an intermediateoperative position; a second cam 14 serves to effect a larger radialoutward movement of the hook butts and thus of the hooks each to anextended operative position, while a cam 15 (which is operationallycoupled to the cam 14) is designed to eifect the withdrawal of the hooksmoved outwardly by the cam 14, in cooperation with the cam profile 2beach to a retracted inoperative position. The withdrawal of the hooksmoved by the cam 13, on the other hand, is effected by the cam profile2a. The cam 13 is controlled by a sheathed flexible cable 16, FIG. 1,which controls the vertical movement of the cam 13 into and out ofengagement with the butts of the welt hooks. A similar control (notshown) is provided for the earns 14 and 15.

The welt hook control effected by the cams 14 and 15, by the cam 13 andby the cam profiles 2a and 2b is such as to cause a limited outwardmovement of the hooks to receive the initial stitches each to an outerintermediate position, a partial withdrawal of the hooks during the weltformation each to an inner intermediate position, an insertion of thehooks for the initial stage of the stitch clearing operation at the endof the welt formation, and the withdrawal of the hooks each to aretracted inoperative position during the continued formation of thearticle after completion of the welt.

FIGS. 5 to 9 illustrate the different operational positions of the welthooks. In these figures, the hooks are references 3A, 3B, 3C, and 3D andthe needle 7A, 7B, 7C, 7D, 7E, 7F, 7G, 7H and 71. The raised needles areindicated by a cross-sectioned rectangle, while those needles which arenot raised are indicated by a bulletshaped outline. It is to be notedthat the hook 3A is substantially aligned with the position of theneedle 7B, the hook 3B with the position of the needle 7D, the hook 3Cwith the position of the needle 7F, and the hook 3D with the position ofthe needle 7H.

When the fabric is to be begun with the welt formation, the hooks arepartially inserted by the cam 13 so that the yarn N is taken by thehooks, whilst only one needle at the end of each group of four adjacentneedles is raised and that is (in FIG. 5), the needles 7A, 7E, and 71.The needle selection is similar to that shown in FIG. 10 and is obtainedin one of the manners well known in connection with welt patterning,under welt formation and tuck stitch or seamless pattern formation. Thehooks can easily be inserted without any danger of damaging contact withthe needles, since the hooks are angularly spaced apart by twice theangular spacing between the needles and only alternate needles areraised. It is to be noted that the hooks have a relatively largethickness, which is permitted by the wide angular spacing betweenadjacent hooks, and the fact that only one hook is individually disposedin each trick 6.

The yarn N, engaged by one needle in four (such as the needles 7A, 7E,71 shown in FIG. 5), serves to form the stitches N (FIG. 6) which remainon the hooks when the latter are partly withdrawn by the cam profile 2aafter formation of the initial stitches. FIG. 6 shows the initial weltstitches, the initial welt portion N and the end portion N of the welt,the welt having been formed by the needles using one or more feeds.

When the welt is finished and the stitches N must be transferred fromthe welt hooks to the needles prior to the knitting of the under-weltand leg, the hooks are inserted further than in FIG. 5 by the cam 14(see FIG. 7), While the needles 7A, 7E and 71 of FIG. 8 are raised.After the insertion of the hooks as shown in FIG. 7, the needles 7C and76 are also raised, i.e. a one and one needle selection as shown in FIG.11. By raising the intermediate one of three lowered needles following aonein-four selection, these intermediate needles (such as 7C and 7G)enter the stitches N and thus the same stitches are engaged by theneedles 7C and 76 when the hooks are withdrawn as shown in FIG. 9, bythe cam 15. In the arrangement of FIG. 9, therefore, the fabric portionsN and N, are knitted together by the initial stitches N The weltformation is thus finished and the under-welt is begun in the usualmanner.

FIGS. 12 and 13 illustrate the relatively greater spaces available forthe hooks 3 in the present arrangement than in the conventionalarrangement (FIG. 12), using double hooks 3x, in spite of the fact thatthe hooks 3 have a greater thickness. Furthermore, the hooks 3 areguided to the edge of the dial, while the tricks for the hooks 3x mustbe enlarged at their outer end such as at Y in FIG. 12.

The drawings illustrate only one example of the invention which can bemodified. For example, according to one possible modification, one mayprovide for a selection of a group of three needles, instead of a groupof four needles. In the first stage, one needle in each three needles israised (that is two needles are not raised), two hooks always projectingbetween two raised needles, to engage the stitch formed by theseneedles. A similar needle selection is effected in the first stage ofthe delivery of the stitches at the end of the welt formation, and inthe second stage of delivery, a second needle in each group of threeneedles is raised to be inserted in the stitch retained by the twohooks.

What I claim is:

A knitting machine of the class described, comprising: a needle cylinderdefining a circumferentially arranged series of uniformly spaced needlepositions; a vertically reciprocable needle in each of said needlepositions; a series of radially movable sinkers cooperating with saidneedles; a dial arranged for rotation in unison with said cylindercoaxially therewith, said dial having a series of radial tricks formedtherein equal in number to one-half the number of said needles, theangular spacing between adjacent tricks being twice the angular spacingbetween adjacent needle positions, the longitudinal axes of said tricksintersecting the longitudinal axes of alternate ones of said needlepositions; a welt hook slidably disposed individually in each trick; andcam means for selectively moving each welt hook between an extendedoperative position, a retracted inoperative position, and at least oneintermediate operative position therebetween, each welt hook, in thecourse of its operation, cooperating with a needle in a positionadjacent to one of said alternate positions, all of said welt hooksbeing inoperative with respect to the needles in said alternatepositions.

References Cited by the Examiner FOREIGN PATENTS 107,642 7/1917 GreatBritain.

DONALD W. PARKER, Primary Examiner.

P. C. FAW, Assistant Examiner.

